How can I pad an integer on the left with zeros?

Question

I have the following variable:

NSNumber *consumption = [dict objectForKey:@\"con\"];

Which returns 42. How can I pad this number to 10 dig

Answer 1

with variable num_digits

NSString* format =[NSString stringWithFormat:@"%%0%zdzd", num_digits];
NSString *theString = [NSString stringWithFormat:format, 42];